BQ2050_15 Datasheet, PDF (12/27 Pages) Texas Instruments – Lithium Ion Power Gauge™ IC

Not Recommended For New Designs
bq2050
The capacity inaccurate flag (CI) is used to warn the
user that the battery has been charged a substantial
number of times since LMD has been updated. The CI
flag is asserted on the 64th charge after the last LMD
update or when the bq2050 is reset. The flag is cleared
after an LMD update.
The CI values are:
FLGS1 Bits
7
65
4
3
2
1
0
-
- - CI -
-
-
-
Where CI is:
0 When LMD is updated with a valid full dis-
charge
1 After the 64th valid charge action with no
LMD updates or the bq2050 is reset
The valid discharge flag (VDQ) is asserted when the
bq2050 is discharged from NAC=LMD. The flag remains
set until either LMD is updated or one of three actions
that can clear VDQ occurs:
n The self-discharge count register (SDCR) has
exceeded the maximum acceptable value (4096
counts) for an LMD update.
n A valid charge action sustained at VSRO > VSRQ for at
least 256 NAC counts.
n The EDV1 flag was set at a temperature below 0°C
The VDQ values are:
FLGS1 Bits
7
65
4
3
2
1
0
-
--
- VDQ -
-
-
Where VDQ is:
0 SDCR ≥ 4096, subsequent valid charge ac-
tion detected, or EDV1 is asserted with the
temperature less than 0°C
1 On first discharge after NAC = LMD
The first end-of-discharge warning flag (EDV1)
warns the user that the battery is almost empty. The
first segment pin, SEG1, is modulated at a 4Hz rate if
the display is enabled once EDV1 is asserted, which
should warn the user that loss of battery power is immi-
nent. The EDV1 flag is latched until a valid charge has
been detected. The EDV1 threshold is externally con-
trolled via the VTS register (see Voltage Threshold Reg-
ister on this page).
The EDV1 values are:
FLGS1 Bits
7 65 4
3
2
-
--
-
-
-
1
0
EDV1 -
Where EDV1 is:
0 Valid charge action detected, VSB ≥ VTS
1 VSB < VTS providing that the discharge rate is
< 2C
The final end-of-discharge warning flag (EDVF) flag
is used to warn that battery power is at a failure condi-
tion. All segment drivers are turned off. The EDVF flag
is latched until a valid charge has been detected. The
EDVF threshold is set 50mV below the EDV1 threshold.
The EDVF values are:
FLGS1 Bits
7 65 4
3
2
-
--
-
-
-
1
0
- EDVF
Where EDVF is:
0 Valid charge action detected, VSB ≥ (VTS -
50mV)
1 VSB < (VTS - 50mV) providing the discharge
rate is < 2C
Temperature Register (TMP)
The read-only TMP register (address=02h) contains the
battery temperature.
TMP Temperature Bits
7
6
5
4
3
21 0
TMP4 TMP3 TMP2 TMP1 -
-
-
-
The bq2050 contains an internal temperature sensor.
The temperature is used to set charge and discharge ef-
ficiency factors as well as to adjust the self-discharge co-
efficient. The temperature register contents may be
translated as shown in Table 7.
The bq2050 calculates the gas gauge bits, GG3-GG0 as a
function of CACH and LMD. The results of the calculation
give available capacity in ¹¹⁶ increments from 0 to ¹⁵¹⁶.
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